Below-ground pitfall traps for standardised monitoring of soil mesofauna: Design and comparison to Berlese/Tullgren funnels

Sampling of soil mesofauna has been traditionally carried out with Berlese/Tullgren extractions, a century old technique. However, sampling methods involving the extractions of soil are becoming increasingly difficult to implement and standardise due to the lack of commercially available equipment. Moreover, they are poorly suited to repeated sampling in the same locations and underestimate more mobile taxa.

Below-ground (hypogean) pitfall trapping is a promising new technique that up to now was only attempted with bulky custom-manufactured tools. In the present work we test a cheap and easily deployable setup made using standard pipe fittings.

The new design was compared across different environments with Berlese/Tullgren extractions in order to ascertain whether they produce similar species lists and detect the same environment-induced changes in communities. The two trap types were found to yield structurally different assemblages, with the new design producing significantly higher abundance and diversity of springtails and larger taxa. Beta-diversity profiles resulted however perfectly comparable, characterising the same pattern of dissimilarities. In addition, a new method is proposed to use the two sampling types in combination to estimate the dispersal of soil organisms.

Below-ground pitfall traps have the potential to complement Berlese extractions for reliable and standardised monitoring of soil arthropods, thanks to their effectiveness, low cost and ease of operation.